The present invention relates generally to the use of conductors in conjunction with waveguides, and more specifically to an assembly which is intended to interconnect a stripline conductor with a waveguide with optimum voltage standing wave ratio (VSWR) and impedance matching.
Systems which use rectangular waveguide radio frequency (RF) connectors all need a means for transitioning between transverse electric (TE) and transverse electromagnetic (TEM) modes. Great progress has been made for performing tranformations between TE and TEM modes in equipment which uses microstrips. However, in addition to microstrips, striplines have been developed for use with waveguides as a substitute for coaxial lines.
A microstrip consists of a strip conductor which is separated from a ground plane by a dielectric. A stripline is distinct from a microstrip in that a stripline has two conducting plates which are separated from each other, with a strip conductor fixed between them. The stripline is roughly equivalent to a flattened coaxial line, with or without dielectric filling. If striplines are to be used in conjunction with rectangular waveguides, a means of effectively coupling wave energy between waveguides and striplines is needed.
The task of coupling wave energy between waveguides and striplines is alleviated, to some extent, by the systems of the following U.S. Patents, the disclosure of which are incorporated by reference:
U.S. Pat. No. 3,483,489 issued to Dietrich;
U.S. Pat. No. 3,579,149 issued to Ramsey;
U.S. Pat. No. 3,732,508 issued to Ito et al;
U.S. Pat. No. 3,755,759 issued to Cohn;
U.S. Pat. No. 3,882,396 issued to Schneider;
U.S. Pat. No. 3,969,691 issued to Saul; and
U.S. Pat. No. 4,143,342 issued to Cain et al.
All of the references cited above are exemplary in the art of performing tranformation between TE modes and TEM modes. Particularly of note is the stripline to waveguide transition system disclosed in the Ito et al reference. Unfortunately, systems which rely on coaxial lines are not effective at frequencies greater than 40 GHz because of the possibilities of undesirable TE and TM moding due to tight tolerances and size requirements. There remains a need for an efficient waveguide to stripline transition for transformation from the TE mode to the TEM mode at frequencies of around 10 GHz as well as EHF (higher than 40 GHz). The present invention is intended to satisfy that need.